Maintenance Following a Very-Low-Calorie Diet

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1 Page 1 of 7 Journal of Consulting and Clinical Psychology June 1997 Vol. 64, No. 3, by the American Psychological Association For personal use only--not for distribution. Maintenance Following a Very-Low-Calorie Diet W. Stewart Agras Robert I. Berkowitz Bruce A. Arnow Christy F. Telch Margaret Marnell Judith Henderson Yvonne Morris Denise E. Wilfley ABSTRACT The authors posed 2 questions in this randomized study of maintenance procedures in which participants were followed for 15 months after completion of a very-low-calorie diet: Would stimulus narrowing during the reintroduction of solid food, achieved by the use of prepackaged foods, improve weight losses and the maintenance of those losses as compared with the use of regular food? Would reintroduction of foods dependent on progress in losing or maintaining weight be superior to reintroduction on a time-dependent basis? Neither the stimulus narrowing condition nor the reintroduction procedure enhanced either maximum weight loss or maintenance of those losses. The stimulus narrowing condition appeared to be poorly tolerated; compliance and attendance were poorer in this condition than in the regular food condition. This research was supported in part by National Institutes of Health Grant DK Optifast-800 was generously provided by the Sandoz Corporation, Minneapolis, Minnesota. Correspondence may be addressed to W. Stewart Agras, Department of Psychiatry, Stanford University School of Medicine, 401 Quarry Road, Room 1322, Stanford, California, Received: April 20, 1995 Revised: August 11, 1995 Accepted: August 17, 1995 As Stamler (1993) pointed out in a recent editorial, obesity has reached epidemic proportions in the United States. Moreover, obesity is accompanied by a variety of serious health problems as well as increased morbidity and mortality ( Bray, 1981 ; Manson et al., 1990 ; Must, Jacques, Dallai, Bajema, & Dietz, 1992 ). The introduction of the very-low-calorie diet (VLCD), which results in relatively large

2 Page 2 of 7 initial weight losses averaging kg in 12 weeks ( Vertes, Genuth, & Hazelton, 1977 ; Wadden, Van Itallie, & Blackburn, 1990 ), raised hopes that an effective treatment was available for the moderately and severely obese. Unfortunately, as Wilson (1994) pointed outand a recent study with the VLCD underlined ( Wadden, Foster, & Letizia, 1994 ), weight regain tends to be inexorable. In the latter study patients treated with a VLCD lost kg but regained almost half of that amount in the year following the end of the fast. It may be that the element leading to the success of the VLCD, that is, caloric restriction in the context of much narrowed food cues, also leads to its failure during the reintroduction of normal foods when patients are faced with an increasing variety of food cues. This possibility led to the principal hypothesis underlying the present study of weight maintenance following a VLCD, namely, that continued narrowing of food stimuli during the reintroduction of normal foods might be associated with continued weight loss and enhanced maintenance of losses. This reasoning was based on the principle of sensory-specific satiety ( Rolls, 1986 ). Both animal and human studies have demonstrated that increasing the variety of foods leads to increased food consumption, which if maintained may lead to obesity. Conversely, decreasing variety leads to decreased consumption ( Kanarak & Hirsch, 1977 ; Rolls, Rowe, Kingston, Megson, & Gunary, 1981 ). Hence, one aim of the present study was to compare reintroduction of solid food following a VLCD under two conditions: with a narrowed range of food stimuli (prepackaged foods) and with regular food. On the basis of the existing literature, it was hypothesized that the narrowed food stimuli would result in greater weight losses and improved maintenance of weight losses as compared with regular food&period It was also hypothesized that in both conditions individualized pacing of the reintroduction on the basis of weight maintenance or further loss (i.e., if weight gain occurred the reintroduction process would be slowed) would prove more effective than a time-based procedure in which food reintroduction would occur regardless of weight changes. These hypotheses led to the following experimental design. All participants in this study first received a 12-week VLCD. If they lost 5% or more of their initial weight, they were allocated at random to one of the following four conditions: (a) refeeding with standard food time dependent; (b) refeeding with standard food weight dependent; (c) refeeding with prepackaged food (stimulus narrowing) time dependent; and (d) refeeding with prepackaged food (stimulus narrowing) weight dependent. All participants received behavior therapy for 9 months following completion of the VLCD and were then followed for 6 months. Participants Method Two hundred one overweight women were entered into this study. Their mean age was 43.7 years SD = 10, the average age of reported onset of overweight was 19.4 years SD = 11.7, and their weight on entry to the VLCD phase of the study was kg SD = 14 with a body mass index (BMI) of 36.6 kg/ m 2 SD = 4.4. Forty-nine percent of the sample had a college degree and more than half of these had attended graduate school; 40% had some college education; and the remainder had completed high school. Before beginning treatment all participants were medically screened, including a full history, physical examination, mental status examination, electrocardiogram, and appropriate blood tests. Exclusion criteria included recent myocardial infarction, major cardiac arrhythmia, or stroke; type-ii diabetes not controlled with oral hypoglycemic agents; bleeding peptic ulcer; or other serious disorders that may complicate dieting (such as liver or kidney disease; evidence of serious mental disorder such as a current psychosis or alcohol or drug abuse; current bulimia nervosa; pregnancy; or taking any medication that may affect appetite).

3 Page 3 of 7 Procedure The study was described in detail to each potential participant, and written informed consent was obtained. Following completion of the initial assessment, all participants were treated with a VLCD combined with behavior therapy in groups of individuals led by experienced doctoral-level therapists for 12 weeks. Six participants dropped out of treatment during the VLCD, and 1 did not meet the entry criterion for the controlled phase of the study, namely, a minimum reduction of 5% of entry body weight. The remaining 194 participants were stratified on BMI and percentage weight loss during the VLCD and allocated at random to one of the four groups listed above. Following randomization, all participants received group behavior therapy weekly for the first 3 months during which food was gradually reintroduced, followed by treatment at 2 week intervals for 3 months, and at monthly intervals for a further 3 months. All treatment was conducted following detailed manuals, and therapists were supervised in a group setting each week. Each therapist conducted at least one group in each of the four experimental conditions. After completing treatment, participants were followed for a further 6 months. Treatment Conditions VLCD. All participants were treated with an 800 kcal/day nutritionally complete diet (Optifast 800, Sandoz Nutrition, Minneapolis, MN) for 12 weeks in the prerandomization phase of the study. Participants consumed five packets of Optifast spread throughout the day and were carefully medically monitored during this phase of treatment. Behavior therapy. The therapy program provided the major behavior change elements associated with weight loss programs, suitably modified in timing and content for use with the VLCD. Participants monitored their own food intake, increased physical activity levels in a graded manner, learned to eat more slowly, and learned to choose foods low in fat and high in complex carbohydrates when the fully varied diet was reintroduced. Various methods were taught to participants concerning handling high-risk situations, and lapses were carefully examined and alternative behaviors developed. These skills were taught at the same time to each group of participants over the 1 year of treatment. However, the mode of reintroduction of food, which occurred over a 3-month period following completion of the VLCD, and the behavioral and educational program associated with each mode, differed between groups. Refeeding with regular food. In the time-dependent condition, regular food gradually replaced the VLCD, beginning with one meal each day (350 added kcal replacing two packets of Optifast) for 2 weeks, two meals daily (700 kcal added replacing two packets of Optifast) for the third week, and three meals each day for the fourth and subsequent weeks of the program (1, 200 kcal replacing the final packet of Optifast). A set of meal plans providing different meals each day together with the correct number of kcal for the particular phase of refeeding was prescribed for each participant. Participants were encouraged to follow this meal plan for the remaining 2 months of this condition. In the weight-dependent version, the participant did not progress to the next stage of food reintroduction unless weight was stable or declining. However, the maximum period in any one stage was 1 month; hence, food was completely reintroduced in 3 months. Stimulus narrowing conditions. The stimulus narrowing condition involved the use of a limited number of prepackaged foods selected to provide the same number of calories and fat, carbohydrate, and protein composition in the same timing

4 Page 4 of 7 as in the regular food conditions. In the time-dependent condition, the participant added one meal per day, using the same prepackaged meal each day for the first week, and a second (but different) prepackaged meal each day for the second week. During the third week a second meal was added, again in prepackaged form, and the third meal was reintroduced in the fourth week of the program. The participant was encouraged to use only the prescribed limited selection of meals for the remaining 2 months of this condition. In the weight-dependent condition, the participant progressed to the next stage only if her weight was stable or declining. However, all three meals were reintroduced by the end of 3 months. As in the case of the regular food condition, participants purchased the prepackaged food. Assessments The data for the randomized phase of this study were collected post-fast (prerandomization), and at 3 months (following reintroduction of food), 6 and 9 months (the latter following completion of treatment), and at 12 and 18 months. The primary outcome measure was weight which was measured using a balance-beam scale. Secondary measures included the Beck Depression Inventory (BDI; Beck, Ward, Mendelson, Mock, & Erbaugh, 1961 ); the State Trait Anxiety Inventory (STAI; Spielberger, Gorsuch, & Lushene, 1970 ); the Family Environment Scale (FES; Moos & Moos, 1981 ); the Locus of Control Scale ( Rotter, 1966 ); and a 10-point disability scale for work, social life, and leisure activities. In addition, measures of the process of treatment were obtained. These included the percentage of group sessions attended, as one aspect of compliance with the program; measures of compliance with the food reintroduction programs derived from self-monitoring forms; and ratings of hunger and food pleasantness before and after the evening meal assessed for 3 days every 2 weeks during the 3-month refeeding phase. Statistical Analyses The primary variable, weight, which was calculated as the percentage of baseline weight lost or gained at each assessment period, was analyzed using a quadratic random regression model. The three parameters of the curve chosen for analysis were the time at which the minimum weight occurred; the maximum weight loss during maintenance; and the rate of increase in weight during follow-up. These parameters were tested using an analysis of variance (ANOVA). The secondary and process variables were also tested using an ANOVA. Results Seventeen participants dropped out of treatment postrandomization 12 (6%) during treatment, and 5 (3%) during follow-up. Of the dropouts, 3 were from the time-dependent regular food condition, 2 were from the weight-dependent regular food condition, 7 were from the time-dependent stimulus narrowing condition, and 5 were from the weight-dependent stimulus narrowing condition. These differences between groups were not statistically significant. Three other participants did not have a complete enough data set to analyze. Hence, the final analyses were conducted on 174 participants, 90% of those entered into the randomized study. The overall average attendance at treatment sessions postrandomization was 80% and 82% for the regular food time-dependent and weight-dependent groups, respectively, and 72% and 78% for the stimulus narrowing time-dependent and weight-dependent groups, respectively. No differences in the rates of attendance between groups were found during the 3-month reintroduction of food phase; however, there was a significant difference between groups F (3, 190) = 2.81, p =.04, for the remainder of treatment. The stimulus narrowing time-dependent group had significantly lower attendance than the

5 Page 5 of 7 weight-dependent regular food condition, F (1, 94) = 7.46, p =.008. All groups demonstrated a significant reduction in attendance over time p < The number of different types of meals (Optifast, regular food, prepackaged food) consumed during the 3-month post-vlcd was derived from the self-monitoring records of each participant, and the adherence to the prescribed regimen was calculated for each participant. The percentages for each of the four groups were compared using a chi-square test, χ 2 6, N = 151 = 13.4, p =.04. The weightdependent regular food group had a significantly better rate of compliance (15% under compliance, 76% full compliance)than the time-dependent regular food group (33% under compliance, 58% full compliance χ 2 2, N = 151 = 6.9, p =.03, and the weight-dependent stimulus narrowing condition (49% under compliance, 46% full compliance) χ 2 2, N = 151 = 10, p =.009, but not the time-dependent stimulus narrowing condition (33% under compliance, 67% full compliance). Weight Change The means and standard deviations for the weight changes (in kilograms) by group over the course of the study (including the loss with the VLCD) are shown in Table 1. No significant between-group differences were found for any of the parameters describing the pattern of weight during maintenance, namely, maximum weight loss, the rate of regain, or the time at which the lowest weight was attained. Because there was a significant difference between groups on adherence to the refeeding regimens, a post hoc analysis was conducted excluding poor adherers. Again, there were no significant differences between groups on any of the weight parameters. Secondary Variables There were no significant between group differences for any of the secondary variables. Process Measures Hunger and pleasantness of food were assessed within each solid meal during the first and last week in which food was introduced. Hunger was significantly reduced from before to after the meal both in the first week, F (1, 97) = 302.3, p =.0001, and the last week, F (1, 99) = 232.8, p =.0001, of food reintroduction. In addition, hunger was significantly greater during the last week of reintroduction than during the first week, F (1, 97) = 22.5, p =.001. The four experimental groups did not differ on this measure. Pleasantness of food did not change significantly either during the meal or over time, and it was not significantly different between groups. Discussion Despite the evidence in animal and human research that narrowing of food stimuli leads to weight loss, there was no difference between groups for any of the parameters describing weight maintenance following a VLCD. Overall, there appeared to be an inexorable and accelerating regain in weight during the 18-month period following the fast. One reason that the stimulus narrowing condition may have failed to improve maintenance as hypothesized was that attendance in the time-dependent mode of this condition and adherence to the weight-dependent mode were significantly worse than the weightdependent regular food condition. The stimulus narrowing condition may have been aversive to participants, leading to poor compliance and attendance. This study adds to the literature demonstrating the steady regain in weight following different types of weight loss programs despite the use of a variety of maintenance procedures ( Brownell, Marlatt, Lichtenstein, & Wilson, 1986 ; Perri et al., 1988 ; Wadden et al., 1994 ; Wilson, 1994 ).

6 Page 6 of 7 One reason for the poor maintenance following the VLCD may be the increase in hunger at mealtimes between the first reintroduction of solid food and the end of this period at 3 months. This finding parallels the average time taken to achieve maximum weight loss in the maintenance phase (i.e., 2.8 months, with weight gain occurring thereafter). One way to decrease hunger would be through the use of appetite suppressant medication. A long-term study of the combination of phentermine and dexfenfluramine suggested that maintenance of weight losses may be improved by the use of such medication ( Weintraub, Sundaresan, Schuster, Moscucci, & Stein, 1992 ). However, a second study examining the use of dexfenfluramine in combination with a VLCD found no advantage for the active drug as compared with a placebo condition after 6 months of treatment ( Andersen, Astrup, & Quaade, 1992 ). In conclusion, this study is another unsuccessful attempt to enhance the maintenance of weight losses, in this case by means of stimulus narrowing of food cues during the refeeding phase of a VLCD. Indeed, the data suggest that in some respects such a procedure may be detrimental, rather than helpful. References Andersen, T., Astrup, A. & Quaade, F. (1992). Dexfenfluramine as adjuvant to alow-calorie formula diet in the treatment of obesity:(a randomized clinical trial. International Journal of Obesity, 16, ) Beck, A. T., Ward, C. H., Mendelson, M., Mock, J. & Erbaugh, J. (1961). An inventory for measuring depression.(archives of General Psychiatry, 20, ) Bray, G. A. (1981). Obesity in America: An overview of the second Fogarty International Center conference on obesity.(international Journal of Obesity, 3, ) Brownell, K. D., Marlatt, G. A., Lichtenstein, E. & Wilson, G. T. (1986). Understanding and preventing relapse.(american Psychologist, 41, ) Kanarak, R. B. & Hirsch, E. (1977). Dietary-induced overeating in experimental animals.(federation Proceedings, 36, ) Manson, J. E., Colditz, G. A., Stampfer, M. J., Willett, W. C., Rosner, B., Monson, R. R., Speizer, F. E. & Hennekens, C. (1990). A prospective study of obesity and risk of coronary heartdisease in women. (New England Journal of Medicine, 322, ) Moos, R. H. & Moos, E. S. (1981). Family Enviroment Scale Manual.(Palo Alto, CA: Consulting Psychologists Press) Must, A., Jacques, P. F., Dallai, G. E., Bajema, C. J. & Dietz, W. H. (1992). Long-term morbidity and mortality of overweight adolescents: A follow-up of the Harvard growth study of 1922 to 1935.(New England Journal ofmedicine, 327, ) Perri, M. G., McAllister, D. A., Gange, J. J., Jordan, R. C., McAdoo, W. G. & Nezu, A. M. (1988). Effects of four maintenance programs on the long-term management of obesity.(journal of Consulting and Clinical Psychology, 56, ) Rolls, B. J. (1986). Sensory-specific satiety.(nutritional Review, 44, ) Rolls, B. J., Rowe, E. A., Kingston, B., Megson, A. & Gunary, R. (1981). Variety in a meal enhances food intake in man.(physiological Behavior, 26, ) Rotter, J. B. (1966). Generalized expectancies for internal versus external control of reinforcement. (Psychological Monographs, 80 (No. 609).) Spielberger, C. D., Gorusch, R. L. & Lushene, R. E. (1970). STAI Manual.(Palo Alto, CA:Consulting Psychologists Press) Stamler, J. (1993). Epidemic obesity in the United States.(Archives of Internal Medicine, 153, ) Vertes, V., Genuth, S. M. & Hazelton, I. M. (1977). Supplemented fasting as a large-scale outpatient program.(journal of the American Medical Association, 238, ) Wadden, T. A., Foster, G. D. & Letizia, K. A. (1994). One-year behavioral treatment of obesity:

7 Page 7 of 7 Comparison of moderate and severe calorie restriction and the effects of weight maintenance therapy. (Journal of Consulting and Clinical Psychology, 62, ) Wadden, T. A., Van Itallie, T. B. & Blackburn, G. L. (1990). Responsible and irresponsible use of verylow-calorie diets in the treatment of obesity.(journal of the American Medical Association, 263, ) Weintraub, M., Sundaresan, P. R., Schuster, B., Moscucci, M. & Stein, E. C. (1992). Long-term weight control: The NHLBI funded multimodal intervention study.(clinical Pharmacology and Therapeutics, 51, ) Wilson, G. T. (1994). Behavioral treatment of obesity: Thirty years and counting.( Advances in Behavior Research and Therapy, 16, ) Table 1.